GB2068517A

GB2068517A - Preventing smoke generation in coke ovens

Info

Publication number: GB2068517A
Application number: GB8102630A
Authority: GB
Original assignee: Mitsubishi Chemical Industries Ltd
Current assignee: Mitsubishi Chemical Corp
Priority date: 1980-01-28
Filing date: 1981-01-28
Publication date: 1981-08-12
Also published as: BE887244A; AU6659181A; US4359362A; DE3102610A1; AU536683B2; FR2474523A1; DE3102610C2; GB2068517B; JPS56104992A; JPS5835637B2; FR2474523B1

Description

1 GB 2 068 517 A 1

SPECIFICATION Preventing smoke generation in coke ovens

This invention relates,to a method and apparatus for preventing generation of black smoke from a coke oven through a chimney after 70 loading raw material coal.

Usually, a coke oven comprises a plurality of juxtaposed and alternately disposed combustion chambers and carburization chambers so that the latter chambers are heated by the heat generated 75 in adjacent combustion chambers and transmitted through walls partitioning adjacent combustion and carburization chambers. The exhaust gases from respective combustion chambers are exhausted from the chimney via sole flue exit 80 ports, hot exhaust valves of respective combustion chambers and a common smoke duct.

In a coke oven provided with a heat storage chamber, the hot exhaust valves are switched at a predetermined interval. Odd numbered hot waste valves and even numbered hot waste valves are alternately switched by a longitudinally reciprocating steel operating strip or bar horizontally disposed above the hot exhaust valves.

When cracks are formed through the partition walls after a long period of use, smoke will issue from the chimney..rhis tends to occur particularly during an interval of about 15 to 20 minutes subsequent to the charging of the raw material coal, in which a large quantity of gas evolves and the gas leaks into the combustion chambers from the carburization chambers thus resulting in an incomplete combustion with the accompanying formation of smoke. Since such smoke causes a public hazard and impairs the cleanliness of the environment it is desirable to reduce as far as possible generation of such smoke.

To prevent the generation of black smoke it is usual to install an electric precipitator in the 105 common smoke duct leading to the chimney. In this method, however, the whole quantity of the exhaust gas generated by the entire coke oven installation is treated so that a large precipitator is necessary because the quantity Gf the exhaust gas 110 is large, 1000 to 2000 Nml/min. for example. Because the concentration of smoke is low this is a relatively expensive way of tackling the problem, both in terms of the cost of installation and operation, having regard to the actual amount of 115 smoke present.

It is an object of this invention to provide a method and apparatus capable of preventing generation of harmful smoke from a coke oven construction with improved efficiency.

According to one aspect of this invention there is provided a method of preventing smoke generation in a coke oven comprising a plurality of juxtaposed and alternately disposed combustion chambers and carburization chambers so that heat 125 generated in the combustion chambers is transmitted to adjacent carburization chambers through partition walls therebetween, each of said combustion chambers being provided with a sole flue exit opening and means for exhausting exhaust gas from respective combustion chambers through a chimney via said sole flue exit openings, hot exhaust valves connected thereto and a common smoke duct, the method using a common smoke conduit and a dust collector contained therein, one end of said common smoke conduit being connected with said chimney, shut off valves connected between the other end of said common smoke conduit and the hot exhaust valves of respective combustion chambers, the method comprising withdrawing exhaust gas from the combustion chambers on the opposite sides of one carburization chamber into which raw material coal has just been loaded, through the sole flue exit ports and said hot exhaust valves associated with said combustion chambers, shutting off a path of the exhaust gas flow from said hot exhaust valves to said common smoke duct, and passing said exhaust gas through said common smoke conduit and said dust collector.

According to another aspect of this invention there is provided an apparatus for preventing generation of smoke from a coke oven having a plurality of juxtaposed and alternately disposed combustion chambers and carburization chambers so that heat generated in the combustion chambers is transmitted to adjacent carburization chambers through partition walls therebetwpen, each of said combustion chambers being provided with a sole flue exit opening, and means for exhausting exhaust gas from respective combustion chambers through a chimney via said sole flue exit openings, hot exhaust valves connected thereto and a common smoke duct, the apparatus comprising a common smoke conduit and a dust collector contained therein, one end of said common smoke conduit being connected with said chimney, shut off valves connected between the other end of said common smoke conduit and the hot exhaust valves of respective combustion chambers and control means for controlling said shut off valves and said hot exhaust valves such that exhaust gas evolved in the combustion chambers on both sides of a carburization chamber which has just been loaded with raw material coal is conveyed to said chimney via said common smoke conduit via said shut off valves, for a predetermined interval after loading said raw material coal. In the accompanying drawings: Fig. 1 is a plan view diagrammatically illustrating a portion of a coke oven embodying the invention for preventing generation of black smoke; and 120 Fig. 2 is a diagrammatic sectional view showing a portion of the coke oven installation. A coke oven 1 is made up of a plurality of juxtaposed and alternately disposed carburization chambers 3, X, W_.. and combustion chambers, 2, 2', 2",..., which are partitioned by partition walls. There are usually 50 to 100 euch chambers in one coke oven. The sole flue exit openings 4, 4', 411.... of respective combustion chambers 2, 2', 21.... are provided with hot exhaust.valves 5, 5', 2 GB 2 068 517 A 2 511.... respectively. Taking the carburization chamber 3' as an example, the lower opening 211 of the hot exhaust valve 5' is connected to a common smoke duct 6 extending in the longitudinal direction of the coke oven 1 by a shut off valve 21' and the common smoke duct 6 is communicated with a chimney 12. The side opening 20' of the hot waste valve 51 is connected with a common exhaust gas duct 10 extending along the coke oven 1 via a shut off valve 7', and an exhaust gas duct 8'. It should be understood that the other hot exhaust valves 51, W and elements associated therewith are constructed and arranged in the same manner. The common exhaust gas duct 10 is connected to the chimney 12 via such dust collector as a back filler, and an electric precipitator 13, a valve 14 and an exhaust fan 15.

The operation of the coke oven described above will now be described taking the carburization 85 chamber 3' as an example. In this case, it is assumed that the exhaust gases of the combustion chambers 2' and 2" on the opposite sides of the carburization chamber 31 are discharged through the hot exhaust valve 5'. This valve 51 is then raised to a position shown in Fig. 2 by the longitudinal movement of the operating rod, not shown, so that there is a tendency for the valve 51 to be sucked towards the smoke conduit 6 by the flow of the exhaust gas passing through the lower opening 2V. Actually, discharge of the exhaust gases of the combustion chambers 2' and 2" is switched to pass alternately through hot exhaust valve 5' and hot exhaust valves 5 and W.

Under these conditions when a charging signal is applied to a coal charging car, not shown, running above the coke oven 1, charging of the raw material coal into the carburization chamber 31 is started, while at the same time, the open and closed states of the hot exhaust valves 5, 5, W and valve members 18, 18' and 1W (only 18' is shown) communicating with the combustion chambers 2 and 2" are confirmed by an electric signal produced by the charging car. Such confirmation can be made depending upon 110 whether valve stems 17, 17' and 17" (only 17' is shown) are raised or lowered, whether the number of the signals produced by a master clock (not shown) for switching the operations of the winches (not shown) operated by the operating rod is an odd or even number, or whether the switching valve for switching the coke oven gas utilized for combustion is open or closed. When it is confirmed that the hot exhaust valves 5 is open and that the hot exhaust valves 5 and W are closed, a fluid piston cylinder assembly 19' of the shut off valve 7', and a fluid piston cylinder assembly 23' for operating the shut off valve 22' juxtaposed to the hot exhaust valve 5' are actuated so as to close the shut off valve 22' for disconnecting the hot exhaust valve 5' from the common smoke conduit 6. The exhaust gases containing smoke and exhausted from the combustion chambers 2' and 2" are discharged or sucked into the common smoke duct 10 from the 130 sole flue exit opening 41 via the hot exhaust valve 5' and the exhaust duct 8', and then discharged & into the chimney via dust collector 13 and exhaust fan 15. Thus, the gas exhausted from the chimney 12 is free from smoke and dust, thereby alleviatingy the problem of public hazard.

The pressure in the exhaust collecting duct 10 is maintained at a reduced pressure of about 10 mm H20 by pressure control valves 11 and 14. The pressure in the exhaust gas duct 8' is maintained at a pressure substantially the same or slightly lower than that at the sole flue exit opening 4' by adjusting a damper 9' contained in the duct 8'.. As above described, when a predetermined time of about 15 to 20 minutes has elapsed after charging the raw material coal or when black smoke is not detected by a smoke detector 16' installed on the inlet side of the valve 5', the fluid pressure piston cylinder assemblies 19' and 23' are actuated to close the shut off valve 7' and open the shut off valve 22. The exhaust gas not containing smoke enters into the smoke duct 6 via opening 2 1' beneath the hot exhaust valve 5' and is then discharged into the atmosphere through the chimney 12.

As above described, although the flow path of the exhaust gas is changed by switching the hot exhaust valves at a predetermined interval, the hot exhaust valves are often switched during the smoke removing treatment. In such a case, the degree of opening of hot exhaust valves 5 and W and the degree of closure of the hot exhaust valves 51 are detected by the movements of the valve stems of the hot exhaust valves 5, 5' and W. An electric signal is produced by the operating rod for switching the operation of winches for operating the hot exhaust gas or by the movement of the switching valve for the coke oven gas utilized for combustion, and according to the result of the detection, the fluid pressure piston cylinder assemblies 19, 191, 19",23,23' and 2W (19, 1911, 23 and 2W are not shown) are actuated, so that shut off valves 71, P and 22' are opened, while shut off valves 7', 22 and 22" are closed. Consequently, the exhaust gases containing smoke and generated in the combustion chambers 2' and 2" are discharged into the exhaust gas collecting duct 10 from side openings 20 and 2W of the hot exhaust valves 5 and W through exhaust gas ducts 8 and W and then removed with smoke by the dust remover 13 in the same manner as above described. Consequently, even if the hot exhaust valves are switched during the smoke removal treatment, this treatment is not interrupted.

Although in the foregoing description, various operations are described as being made automatically, it is also possible to open and close shut off valves manually while observing the degree of opening and closing of the hot exhaust valves.

Furthermore, instead of intercepting the communication between the lower opening of a hot exhaust valve (for example 5') and the smoke 3 GB 2 068 517-A 3 conduit 6 with a shut off valve 22, the valve member 18' can directly close the lower opening. 65 To this end, the valve stem 17' may be operated by a fluid pressure piston cylinder assembly, or a cam or cable etc. operated by an operating member extending longitudinally above the coke oven.

The above described smoke removing treatment is carried out each time the raw material coal is loaded in respective carburization chambers. When the interval of raw material loading operations is substantially equal to the time necessary for removing smoke, the exhaust gas of a combustion chamber now to be loaded with the raw material coal is admitted into the exhaust gas collecting duct by controlling various valves with an electric signal from a raw material loading car while at the same time the fluid pressure piston cylinder assemblies are actuated to admit the combustion exhaust gas into the smoke duct 6 from a combustion chamber which was loaded with coal at a preceding time.

Since according to this invention, the exhaust gases are removed and subjected to the dust removing treatment from only the combustion chambers on both sides of a carburization chamber loaded with raw material coal and for only a short time subsequent to the coal loading, the concentration of the smoke in the exhaust gas to be treated is low and the quantity of the gas to be treated is small thus not only improving the efficiency of smoke removal but also decreasing the cost of installation and running.

Claims

1. A method of preventing smoke generation in a coke oven comprising a plurality of juxtaposed and alternately disposed combustion chambers and carburization chambers so tha heat generated in the combustion chambers is transmitted to adjacent carburization chambers through partition walls therebetween, each of said combustion chambers being provided with a sole flue exit opening and means for exhausting exhaust gas from respective combustion chambers through a chimney via said sole flue exit openings, hot exhaust valves connected thereto and a common smoke duct, the method using a common smoke conduit and a dust collector contained therein, one end of said common smoke conduit being connected with said chimney, shut off valves connected between the other end of said common 115 smoke conduit and the hot exhaust valves of respective combustion chambers, the method comprising withdrawing exhaust gas from the combustion chambers on the opposite sides of one carburization chamber into which raw material coal has just been loaded, through the sole flue exit ports and said hot exhaust.valves associated with said combustion chambers, shutting off a path of the exhaust gas flow from said hot exhaust valves to said common smoke duct, and passing said exhaust gas through said common smoke conduit and said dust collector.

2. A method according to claim 1, wherein said exhaust gas is passed through said common smoke conduit and said collector for a predetermined interval after loading the raw material coal into said carburization chambers and then said exhaust gas is passed into said common smoke duct from said hot exhaust valves at the end of said predetermined interval.

3. A method of preventing smoke generation in a coke oven, substantially as herein described with reference to the accompanying drawings. 75

4. An apparatus for preventing generation of smoke from a coke oven having a plurality of juxtaposed and alternately disposed combustion chambers and carburization chambers so that heat generated in the combustion chambers is transmitted to adjacent carburization chambers through partition walls therebetween, each of said combustion chambers being provided with a sole flue exit opening, and means for exhausting exhaust gas from respective combustion chambers through a chimney via said sole flue exit openings, hot exhaust valves connected thereto and a common smoke duct, the apparatus compkising a -common smoke conduit and a dust collector contained therein, one end of said common smoke conduit being connected with said chimney, shut off valves connected between the other end of said common smoke conduit and the hot exhaust valves of respective combustion chambers, and control means for controlling said shut off valves and said hot exhaust valves such that exhaust gas evolved in the combustion chambers on both sides of a carburization chamber which has just been loaded with raw material coal is conveyed to said chimney via said common smoke conduit via said shut off valves, for a predetermined interval after loading said raw material coal.

5. An apparatus according to claim 4, wherein said apparatus further comprises shut off valves respectively disposed between said common smoke duct and respective hot exhaust valves.

6. An apparatus according to claim 5 wherein said hot exhaust valve is used as said shut off valve disposed at an inlet of said common smoke duct.

7. An apparatus according to claim 4, 5, or 6, which further comprises a smoke detector installed between the sole flue exit port and the hot exhaust valve of each combustion chamber for controlling said control means.

8. An apparatOs according to any one of claims 4 to 7, which further comprises dampers each disposed between said shut off valve and said common smoke conduit for maintaining pressure in a conduit connected therebetween at a pressure substantially equal or slightly lower than a pressure at each sole flue exit.

9. An apparatus according to any one of claims 4 to 8, which further comprises an exhaust fan connected in said common smoke conduit.

10. An apparatus according to any one of claims 4 to 9, which further comprises pressure 4 GB 2 068 517 A 4 control valve means connected in said common smoke conduit.

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11. An apparatus for preventing smoke Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.

generation in a coke oven, substantially as herein described with reference to the accompanying A drawings.

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